In addition to other applicable provisions of law pertaining to conflicts of interest of public officials, no board member, appointive or otherwise, may participate in any decision on any board contract in which the board member has any interests, direct or indirect, with any firm, partnership, corporation, or association which would be the recipient of any aid under this chapter. In any instance where the participation occurs, the board shall void the transaction, and the involved member shall be subject to whatever further sanctions may be provided by law. The board shall frame and adopt a code of ethics for its members, which shall be designed to protect the state and its citizens from any unethical conduct by the board.